#include "erfa.h" void eraP06e(double date1, double date2, double *eps0, double *psia, double *oma, double *bpa, double *bqa, double *pia, double *bpia, double *epsa, double *chia, double *za, double *zetaa, double *thetaa, double *pa, double *gam, double *phi, double *psi) /* ** - - - - - - - - ** e r a P 0 6 e ** - - - - - - - - ** ** Precession angles, IAU 2006, equinox based. ** ** Given: ** date1,date2 double TT as a 2-part Julian Date (Note 1) ** ** Returned (see Note 2): ** eps0 double epsilon_0 ** psia double psi_A ** oma double omega_A ** bpa double P_A ** bqa double Q_A ** pia double pi_A ** bpia double Pi_A ** epsa double obliquity epsilon_A ** chia double chi_A ** za double z_A ** zetaa double zeta_A ** thetaa double theta_A ** pa double p_A ** gam double F-W angle gamma_J2000 ** phi double F-W angle phi_J2000 ** psi double F-W angle psi_J2000 ** ** Notes: ** ** 1) The TT date date1+date2 is a Julian Date, apportioned in any ** convenient way between the two arguments. For example, ** JD(TT)=2450123.7 could be expressed in any of these ways, ** among others: ** ** date1 date2 ** ** 2450123.7 0.0 (JD method) ** 2451545.0 -1421.3 (J2000 method) ** 2400000.5 50123.2 (MJD method) ** 2450123.5 0.2 (date & time method) ** ** The JD method is the most natural and convenient to use in ** cases where the loss of several decimal digits of resolution ** is acceptable. The J2000 method is best matched to the way ** the argument is handled internally and will deliver the ** optimum resolution. The MJD method and the date & time methods ** are both good compromises between resolution and convenience. ** ** 2) This function returns the set of equinox based angles for the ** Capitaine et al. "P03" precession theory, adopted by the IAU in ** 2006. The angles are set out in Table 1 of Hilton et al. (2006): ** ** eps0 epsilon_0 obliquity at J2000.0 ** psia psi_A luni-solar precession ** oma omega_A inclination of equator wrt J2000.0 ecliptic ** bpa P_A ecliptic pole x, J2000.0 ecliptic triad ** bqa Q_A ecliptic pole -y, J2000.0 ecliptic triad ** pia pi_A angle between moving and J2000.0 ecliptics ** bpia Pi_A longitude of ascending node of the ecliptic ** epsa epsilon_A obliquity of the ecliptic ** chia chi_A planetary precession ** za z_A equatorial precession: -3rd 323 Euler angle ** zetaa zeta_A equatorial precession: -1st 323 Euler angle ** thetaa theta_A equatorial precession: 2nd 323 Euler angle ** pa p_A general precession ** gam gamma_J2000 J2000.0 RA difference of ecliptic poles ** phi phi_J2000 J2000.0 codeclination of ecliptic pole ** psi psi_J2000 longitude difference of equator poles, J2000.0 ** ** The returned values are all radians. ** ** 3) Hilton et al. (2006) Table 1 also contains angles that depend on ** models distinct from the P03 precession theory itself, namely the ** IAU 2000A frame bias and nutation. The quoted polynomials are ** used in other ERFA functions: ** ** . eraXy06 contains the polynomial parts of the X and Y series. ** ** . eraS06 contains the polynomial part of the s+XY/2 series. ** ** . eraPfw06 implements the series for the Fukushima-Williams ** angles that are with respect to the GCRS pole (i.e. the variants ** that include frame bias). ** ** 4) The IAU resolution stipulated that the choice of parameterization ** was left to the user, and so an IAU compliant precession ** implementation can be constructed using various combinations of ** the angles returned by the present function. ** ** 5) The parameterization used by ERFA is the version of the Fukushima- ** Williams angles that refers directly to the GCRS pole. These ** angles may be calculated by calling the function eraPfw06. ERFA ** also supports the direct computation of the CIP GCRS X,Y by ** series, available by calling eraXy06. ** ** 6) The agreement between the different parameterizations is at the ** 1 microarcsecond level in the present era. ** ** 7) When constructing a precession formulation that refers to the GCRS ** pole rather than the dynamical pole, it may (depending on the ** choice of angles) be necessary to introduce the frame bias ** explicitly. ** ** 8) It is permissible to re-use the same variable in the returned ** arguments. The quantities are stored in the stated order. ** ** Reference: ** ** Hilton, J. et al., 2006, Celest.Mech.Dyn.Astron. 94, 351 ** ** Called: ** eraObl06 mean obliquity, IAU 2006 ** ** Copyright (C) 2013-2015, NumFOCUS Foundation. ** Derived, with permission, from the SOFA library. See notes at end of file. */ { double t; /* Interval between fundamental date J2000.0 and given date (JC). */ t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC; /* Obliquity at J2000.0. */ *eps0 = 84381.406 * ERFA_DAS2R; /* Luni-solar precession. */ *psia = ( 5038.481507 + ( -1.0790069 + ( -0.00114045 + ( 0.000132851 + ( -0.0000000951 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Inclination of mean equator with respect to the J2000.0 ecliptic. */ *oma = *eps0 + ( -0.025754 + ( 0.0512623 + ( -0.00772503 + ( -0.000000467 + ( 0.0000003337 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Ecliptic pole x, J2000.0 ecliptic triad. */ *bpa = ( 4.199094 + ( 0.1939873 + ( -0.00022466 + ( -0.000000912 + ( 0.0000000120 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Ecliptic pole -y, J2000.0 ecliptic triad. */ *bqa = ( -46.811015 + ( 0.0510283 + ( 0.00052413 + ( -0.000000646 + ( -0.0000000172 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Angle between moving and J2000.0 ecliptics. */ *pia = ( 46.998973 + ( -0.0334926 + ( -0.00012559 + ( 0.000000113 + ( -0.0000000022 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Longitude of ascending node of the moving ecliptic. */ *bpia = ( 629546.7936 + ( -867.95758 + ( 0.157992 + ( -0.0005371 + ( -0.00004797 + ( 0.000000072 ) * t) * t) * t) * t) * t) * ERFA_DAS2R; /* Mean obliquity of the ecliptic. */ *epsa = eraObl06(date1, date2); /* Planetary precession. */ *chia = ( 10.556403 + ( -2.3814292 + ( -0.00121197 + ( 0.000170663 + ( -0.0000000560 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Equatorial precession: minus the third of the 323 Euler angles. */ *za = ( -2.650545 + ( 2306.077181 + ( 1.0927348 + ( 0.01826837 + ( -0.000028596 + ( -0.0000002904 ) * t) * t) * t) * t) * t) * ERFA_DAS2R; /* Equatorial precession: minus the first of the 323 Euler angles. */ *zetaa = ( 2.650545 + ( 2306.083227 + ( 0.2988499 + ( 0.01801828 + ( -0.000005971 + ( -0.0000003173 ) * t) * t) * t) * t) * t) * ERFA_DAS2R; /* Equatorial precession: second of the 323 Euler angles. */ *thetaa = ( 2004.191903 + ( -0.4294934 + ( -0.04182264 + ( -0.000007089 + ( -0.0000001274 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* General precession. */ *pa = ( 5028.796195 + ( 1.1054348 + ( 0.00007964 + ( -0.000023857 + ( 0.0000000383 ) * t) * t) * t) * t) * t * ERFA_DAS2R; /* Fukushima-Williams angles for precession. */ *gam = ( 10.556403 + ( 0.4932044 + ( -0.00031238 + ( -0.000002788 + ( 0.0000000260 ) * t) * t) * t) * t) * t * ERFA_DAS2R; *phi = *eps0 + ( -46.811015 + ( 0.0511269 + ( 0.00053289 + ( -0.000000440 + ( -0.0000000176 ) * t) * t) * t) * t) * t * ERFA_DAS2R; *psi = ( 5038.481507 + ( 1.5584176 + ( -0.00018522 + ( -0.000026452 + ( -0.0000000148 ) * t) * t) * t) * t) * t * ERFA_DAS2R; return; } /*---------------------------------------------------------------------- ** ** ** Copyright (C) 2013-2015, NumFOCUS Foundation. ** All rights reserved. ** ** This library is derived, with permission, from the International ** Astronomical Union's "Standards of Fundamental Astronomy" library, ** available from http://www.iausofa.org. ** ** The ERFA version is intended to retain identical functionality to ** the SOFA library, but made distinct through different function and ** file names, as set out in the SOFA license conditions. The SOFA ** original has a role as a reference standard for the IAU and IERS, ** and consequently redistribution is permitted only in its unaltered ** state. The ERFA version is not subject to this restriction and ** therefore can be included in distributions which do not support the ** concept of "read only" software. ** ** Although the intent is to replicate the SOFA API (other than ** replacement of prefix names) and results (with the exception of ** bugs; any that are discovered will be fixed), SOFA is not ** responsible for any errors found in this version of the library. ** ** If you wish to acknowledge the SOFA heritage, please acknowledge ** that you are using a library derived from SOFA, rather than SOFA ** itself. ** ** ** TERMS AND CONDITIONS ** ** Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions ** are met: ** ** 1 Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** ** 2 Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** ** 3 Neither the name of the Standards Of Fundamental Astronomy Board, ** the International Astronomical Union nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 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